The present invention is related to a switch for switching both variable-length packets and fixed-length ATM cells. More specifically, the present invention is related to a switch for switching both variable-length packets and fixed-length ATM cells using a segmentation function to convert a packet to cells and a reassembly function to convert the packet to cells.
In a system where both variable-length packets and fixed-length ATM cells must be handled, it is typically necessary to choose a xe2x80x9cnativexe2x80x9d format (cells or packets) for all data to traverse the system. It is necessary to convert xe2x80x9cnon-nativexe2x80x9d traffic to the xe2x80x9cnativexe2x80x9d format on the ingress side of the system. This typically places burdens on any xe2x80x9cnon-nativexe2x80x9d traffic in the forms of added design complexity, potentially reduced performance, and added cost.
The present invention describes a way by which both ATM cells and packets can be sent through the system and then converted on the egress side of the system. This eliminates the need to convert from packets to cells or cells to packets on the ingress side of the system. This results in improved overall system performance. Converting cells to packets or packets to cells adds delay/overhead. Receiver makes right only adds this delay/overhead on paths necessary, at output where other ports are unaffected. A switch which stripes data onto multiple fabrics and sends parity data to another fabric has been described in U.S. patent application Ser. No. 09/333,450, incorporated by reference herein. See also U.S. patent application Ser. No. 09/293,563 which describes a wide memory TDM switching system, incorporated by reference herein.
The present invention pertains to a switch for switching fixed size ATM cells and variable length packets of a network. The switch comprises an input port mechanism having a plurality of input ports each able to receive cells and packets from the network. The switch comprises an output port mechanism having a plurality of output ports each able to send cells and packets to the network. The switch comprises a switching fabric connected to the input port mechanism and the output port mechanism for switching either packets or cells from any input port to any output port. The switch comprises a mechanism for converting packets to cells when the input port is a packet port and the output port is a cell port and cells to packets when the input port is a cell port and the output port is a packet port, respectively, or not converting cells or packets when the input port and the output port are both cell ports or both packet ports, respectively. The converting mechanism is connected to the output port mechanism and the switching fabric.
The present invention pertains to a communications system. The system comprises an Ethernet along which packets travel. The system comprises an ATM network along which ATM cells travel. The system comprises a switch connected to the Ethernet and the ATM network which converts packets received from the Ethernet into ATM cells to be sent to the ATM network, and converts ATM cells received from the ATM network to packets to be sent to the Ethernet.
The present invention pertains to a method for transferring fixed size ATM cells and variable size packets in a network. The method comprises the steps of receiving fixed size ATM cells at a first input port of the switch. Then there is the step of directing the fixed size ATM cells from the input port to a mechanism for converting the ATM cells to variable length packets with a switching fabric. Next there is the step of converting the ATM cells to variable length packets with the converting mechanism. Then there is the step of sending the variable length packets away from the switch through a first output port of the switch.